Standoffish (adjective)

1. Reserved and aloof in manner, not friendly or approachable.
2. Cold, distant, and unwilling to get close to others.

Origin:

From the phrase "to stand off" meaning to be distant, reserved or aloof.

Examples:

1. She was known to be standoffish and didn't make friends easily.
2. He was standoffish with strangers and took a while to warm up to people.
3. The new employee was standoffish and didn't participate in office conversations.
4. She had a standoffish attitude and didn't want to be bothered.
5. He had a standoffish demeanor and didn't make an effort to socialize with others.